What is the term for the pressure exerted by water in the soil voids?

The term for the pressure exerted by water in the soil voids is referred to as pore water pressure. This concept is crucial in geotechnical engineering, as pore water pressure influences the effective stress within soil. Effective stress is the stress carried by the soil skeleton and is calculated by subtracting the pore water pressure from the total stress in a soil mass. Pore water pressure is particularly significant in saturated soils, where the water fills the voids between soil particles, creating a pressure that can affect the stability and behavior of the soil.

When analyzing soil conditions, understanding pore water pressure helps in evaluating the risk of phenomena such as liquefaction, slope stability, and consolidation of soils. This pressure plays a major role in determining the effective stress, thus influencing the mechanical properties of the soil structure, such as shear strength.

While hydrostatic pressure relates to the pressure in a fluid at rest due to gravity, and Laplace pressure pertains to the pressure difference across the interface of two fluids, these terminologies do not specifically address the context of pore water pressure in soil mechanics.